Syringe with improved needle retraction mechanism

Abstract

The present invention relates to a syringe having an improved needle retraction mechanism, the syringe comprising: (a) a cylindrical barrel; (b) a needle holder; (c) a hollow plunger; (d) a rod; (e) an extractor element; and (f) a restoring tension or compression spring, the extractor element being movable so as to be displaceable from an advanced position to a retracted position, the extractor element having a male protrusion that protrudes in the advanced position and engages an internal cavity of the needle holder to couple the extractor element to the needle holder; and a hook means defining a connection between the plunger and the extractor element, the axial bore of the plunger being defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outward to expand the axial bore of the plunger, thereby disengaging the extractor element from the plunger and retracting it toward a retracted position. The present invention also relates to a syringe kit, the syringe comprising the improved needle retraction mechanism as described herein.

Description

[Technical Field]

[0001] The present invention relates to a safety syringe with a retractable needle.

[0002] More particularly, the present invention relates to a syringe with an improved needle retraction mechanism. [Background technology]

[0003] Medical syringes are well known in the industry and consist of a wide variety of designs, each with its own unique benefits and uses. Certain syringes are associated with so-called safety syringes, which serve to protect healthcare workers and others from accidental needlestick injuries and prevent syringe reuse. The dangers associated with reusing used syringes and the problems associated with leaving them in public places are well known. In recent years, the importance of safety syringes has increased as many governments and safety authorities have begun to focus on needlestick injuries and the prevention of reuse.

[0004] However, a common problem associated with current safety syringes is their relative complexity and / or confusing operation. Healthcare professionals operating safety syringes often do not understand how to engage the mechanisms that retract the needle and / or safely lock the needle within the syringe. Furthermore, even if the mechanisms are engaged, the healthcare professional cannot be sure whether the needle has been retracted correctly and / or whether the retraction is fully completed. Furthermore, current retraction mechanisms unnecessarily complicate the syringe design, resulting in several other inherent drawbacks, such as partial watertightness and / or airtightness and inaccurate fluid dosing. These drawbacks further increase the anxiety of healthcare professionals, as they can no longer be certain of the correct injection volume.

[0005] A safety syringe with a retractable needle is illustrated in EP 0505330 (Patent Document 1). While this syringe has a practical needle retraction mechanism, medical personnel must receive detailed instructions on how to operate the syringe correctly. While a typical syringe is operated by simply depressing the plunger rod until the syringe is empty, syringes designed according to EP 0505330 require careful handling. The first extrusion stroke empties the syringe. However, to engage the retraction mechanism, the operator must consciously depress the plunger rod further in a second extrusion stroke. This second extrusion stroke is not only counterintuitive, but also makes it very difficult to determine when the needle retraction has been engaged and whether it has been fully retracted. Additionally, the retraction mechanism of EP 0505330 has two stages: first, the needle holder is coupled to the extractor element; and, only in the second stage, the retraction mechanism engages and the needle is actually retracted. Thus, it is possible for an operator to intentionally or unintentionally only engage the retraction mechanism.

[0006] Another safety syringe is disclosed in U.S. Patent No. 5,190,526 (US 5,190,526). The retraction mechanism is very complicated because the syringe barrel wall is molded to fit multiple spherical bearings. The unusual shape of the syringe barrel inevitably reduces the watertightness and / or airtightness of the seal between the plunger and the barrel, significantly reducing the quantitative accuracy of liquid administration. Therefore, a medical professional operating the syringe disclosed in U.S. Patent No. 5,190,526 would be uncertain about the exact volume injected. Additionally, because the retraction mechanism of U.S. Patent No. 5,190,526 consists of two retraction stages, the operator would be uncertain about whether the retraction mechanism was properly engaged. Furthermore, U.S. Patent No. 5,190,526 (WO 91 / 03269) and European Patent Application Publication No. 2,229,968 (EP 2229968) describe syringes with safety retraction mechanisms. Patent Document 5 (JP H05 503437) describes a prefilled syringe. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] European Patent Application Publication No. 0505330 [Patent Document 2] U.S. Patent No. 5,190,526 [Patent Document 3] International Publication No. 91 / 03269 Brochure [Patent Document 4] European Patent Application Publication No. 2,229,968 [Patent Document 5] Special Publication No. 5-503437 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention aims to solve at least some of the problems and drawbacks mentioned above.

[0009] The present invention and its embodiments can be used to provide a solution to one or more of the above-mentioned drawbacks. To this end, the present invention relates to a syringe with an improved needle retraction mechanism as claimed in claim 1, which has the advantage of being intuitive to operate for medical personnel or others. [Means for solving the problem]

[0010] The present invention can be operated similarly to a conventional syringe, with the retraction mechanism automatically engaging as soon as the syringe is emptied. By providing a bendable flange on the plunger, the retraction mechanism can be engaged with a single fluid transfer motion, consistent with conventional syringe operation. Therefore, the syringe of the present invention eliminates the operator's doubts about whether the retraction engagement was performed correctly and / or completely, and prevents the operator from reusing the syringe. Furthermore, because no volume adjustments to the barrel are required, optimal injection accuracy is maintained.

[0011] A preferred embodiment of the device is as set out in any of claims 2 to 14.

[0012] The present invention also relates to a syringe kit, preferably a prefilled syringe kit with needle retraction mechanism as claimed in claim 15, which has the advantages of being ready to use, safe to use and intuitive for medical personnel and others to operate.

[0013] The present invention has the advantage that it can be operated in the same way as a normal syringe, and the retraction mechanism automatically engages as soon as the syringe is empty. By providing a bendable flange on the plunger, the retraction mechanism can be engaged with a single fluid transfer motion, just like a normal syringe. Therefore, the syringe kit of the present invention eliminates the operator's doubts about whether the retraction engagement was performed correctly and / or completely, and prevents the operator from reusing the syringe. Furthermore, because no volume adjustments to the barrel are required, optimal accuracy of the injection volume is maintained. The syringe kit, which is comprised of two parts, a syringe assembly and an injection assembly, also has the advantage that the syringe kit can be configured as a kit that can be both assembled and disassembled.

[0014] In some embodiments of the invention, the syringe is a pre-filled syringe.

[0015] Preferred embodiments of the syringe kit are set forth in any of the dependent claims.

[0016] The present invention also relates to a method for using the syringe kit according to claim 27.

[0017] In a final aspect, the present invention relates to a method for producing a syringe kit according to claim 28. [Brief explanation of the drawings]

[0018] [Figure 1A] FIG. 1 is a general view of a syringe according to an embodiment of the present invention in an advanced position prior to engagement of a needle retraction mechanism. [Figure 1B] FIG. 1 is a general view of a syringe according to an embodiment of the present invention in a retracted position after engagement of the needle retraction mechanism. [Figure 2A] FIG. 10 is a detailed view of a needle retraction mechanism of a syringe according to an embodiment of the present invention prior to engagement of the needle retraction mechanism. [Figure 2B] FIG. 10 is a detailed view of a needle retraction mechanism of a syringe according to an embodiment of the present invention during engagement of the needle retraction mechanism. [Figure 2C] 10 is a detailed view of a needle retraction mechanism of a syringe according to an embodiment of the present invention at a point further into the engagement of the needle retraction mechanism. FIG. [Figure 3] FIG. 10 is a detailed view showing a needle retraction mechanism of a syringe according to an embodiment of the invention, including a sealing ring fitted between the extractor element and the hollow plunger. [Figure 4] FIG. 10 is a detailed view of a needle retraction mechanism of a syringe according to an embodiment of the invention, including a sealing ring fitted between the extractor element and the hollow plunger, and a fitting for a replaceable needle holder; [Figure 5] 1 shows a general view of a syringe kit according to an embodiment of the present invention in an advanced position before engagement of a needle retraction mechanism. FIG. [Figure 6] FIG. 1 is a general view of a syringe kit according to an embodiment of the present invention in a retracted position after engagement of the needle retraction mechanism. [Figure 7] 10A-10C show an embodiment of the invention in which the hollow nose end of the needle holder further comprises an internal annular ring. [Figure 8] FIG. 10 shows an embodiment of the invention in which the extractor element further comprises a dead space filler and the inner surface of the plunger comprises an annular ring. [Figure 9] A plunger cap and retractor element are shown with a plurality of spring retaining fins that retain the proximal and distal ends of the restoring tension spring to the plunger cap and extractor element, respectively. [Figure 10] A gasket is provided between the outer surface of the needle holder and the inner surface of the hollow nose of the barrel. DETAILED DESCRIPTION OF THE INVENTION

[0019] The present invention relates to a syringe with an improved needle retraction mechanism.

[0020] Unless otherwise defined, all terms used in disclosing the present invention, including technical and scientific terms, have the meanings commonly understood by one of ordinary skill in the art to which this invention belongs. As a further guide, term definitions are included to better understand the teachings of the present invention.

[0021] As used herein, the following terms have the following meanings:

[0022] As used herein, "a," "an," and "the" refer to both the singular and the plural unless the context clearly dictates otherwise. By way of example, "a compartment" refers to one or more compartments.

[0023] As used herein, "comprise," "comprising," and "comprises," "comprised of" are synonymous with "include," "including," "includes," or "contain," "containing," or "contains," and are inclusive or open-ended terms that specify the presence of what follows, e.g., components, but do not exclude or preclude the presence of additional, unspecified components, features, elements, materials, or steps that are known in the art or disclosed therein.

[0024] Furthermore, the terms first, second, third, etc. in this specification and claims are used to distinguish between similar elements and not necessarily to describe a sequential or chronological order, unless otherwise specified. The terms so used are interchangeable where appropriate, and it will be understood that the embodiments of the invention described herein are capable of operating in sequences other than those described or illustrated herein.

[0025] The recitation of numerical ranges specified by boundaries includes not only the boundaries recited but all values ​​and fractions subsumed within that range.

[0026] The terms "one or more", "at least one", etc., such as one, two or more, or at least one of the components forming a group, are clear in themselves, but by way of further illustration, this term means in particular including any one of said components, any two or more of said components, such as any ≧3, ≧4, ≧5, ≧6 or ≧7 of said components, and even including all of said components.

[0027] A first aspect of the present invention relates to a syringe having an improved needle retraction mechanism, a. a cylindrical barrel including a hollow body and a hollow nose end; b. a needle holder disposed in the nose end, the needle holder including an internal cavity; c. a hollow plunger disposed within the hollow body of the cylindrical barrel; d. a rod connected to or integral with said plunger and extending within said hollow body of said cylindrical barrel, said rod and said plunger each having an axial bore extending therethrough; e. an extractor element disposed inside the axial bore of the plunger and the bore of the rod; f. a restoring tension or compression spring connected to the extractor element; Equipped with the extractor element is movable so as to be displaceable between an advanced position in which a portion of the extractor element protrudes beyond the distal end of the plunger or from the plunger toward the needle holder and is surrounded by the plunger, and a retracted position in which the extractor element is fully retracted into the rod and is spaced apart from the needle holder, the extractor element having a male protrusion protruding beyond the distal end of the plunger or from the plunger in the advanced position for engaging an internal cavity of the needle holder to couple the extractor element to the needle holder, and a hook means defining a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and the recovery spring in tension or compression, the axial bore of the plunger being defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outward and expanding the axial bore of the plunger, thereby disengaging the extractor element from the plunger and retracting it towards the retracted position.

[0028] In the context of the present invention, the term "syringe" refers to a simple reciprocating pump that includes a "plunger" or "piston" that is tightly fitted within a cylindrical tube called a "barrel." The plunger can be pulled or pushed linearly along the inside of the barrel, thereby enabling the syringe to draw in or expel fluid through a discharge orifice located at the nose end of the barrel. In accordance with the present invention, a needle holder is attached to the nose end, which comprises a needle, e.g., a hypodermic needle. Syringes such as those described herein are frequently used in clinical medicine to administer injections or to inject fluids into the bloodstream.

[0029] The term "needle retraction mechanism" refers to any mechanism that allows the needle holder containing the needle within the syringe to be automatically retracted to prevent the syringe from being reused and / or to reduce the risk of needlestick injuries.

[0030] The terms "plunger" and "rod," and in particular the phrase "the plunger connected to the rod," should be interpreted as either one element or multiple elements, both of which are known in the art. In particular, the plunger and rod can be provided as one element, or can be configured as separate elements that are typically interconnected using a connecting means.

[0031] The term "extractor element" refers to the specific element of the retraction mechanism that extracts and retracts the needle into the syringe. In accordance with the present invention, the actual retraction is accomplished by a "recovery tension or compression spring," which indicates that the spring is in a tensioned or compressed state during use of the syringe and compresses or expands to a resting state upon engagement of the retraction mechanism, thereby retracting the extractor element and its associated needle holder. In this context, the position before retraction is referred to as the "advanced position," and the position after retraction is referred to as the "retracted position."

[0032] The term "hooking means" refers to any means for interconnecting two or more elements and allowing them to be reconnected. Specific hooking means include complementary protrusions and / or recesses, high friction or adhesion areas, etc.

[0033] The term "bendable flange" herein refers to any bendable part extending from the plunger towards the needle holder, the nature of which bending is the result, for example, of providing a deformable material, making the flange a predetermined thinness, etc.

[0034] The syringe of the present invention has a significantly improved needle retraction mechanism, offering the advantage of being intuitive for medical professionals and others. The present invention operates similarly to a conventional syringe, with the retraction mechanism automatically engaging as soon as the syringe is empty. Self-locking syringes known in the art typically require multiple and / or additional steps by the operator to engage the mechanism. That is, the plunger must be pushed further forward even though the syringe is already empty, or the needle holder must be coupled to the extractor element and the extractor element must be decoupled from the plunger in separate movements. However, the present invention provides a bendable flange on the plunger, allowing the retraction mechanism to be engaged with a single fluid transfer motion, consistent with conventional syringe operation. The distal end of the male protrusion on the extractor element is generally conical, creating a steep angle along which the bendable grip of the needle holder can slide, thereby requiring only a small bending of the bendable grip to engage the male protrusion. Furthermore, the entrance to the needle holder cavity formed by the bendable grip of the needle holder is characterized by a conical recess complementary to the distal end of the male protrusion. In this way, the perceptible resistance felt by the user is advantageously kept to a minimum. The outer periphery of the bendable grip of the needle holder also has a substantially angled outer surface, which advantageously further reduces the resistance felt by the user when the bendable flange of the hollow plunger rides over the angled outer surface of the needle holder. The only tactile feedback provided to the user during syringe operation is the plunger reaching the end of the barrel and the impact of the extractor element against the retraction spring during needle retraction. As a result, the syringe of the present invention leaves the operator in no doubt as to whether retraction was performed correctly and / or completely, eliminating the possibility of the operator reusing the syringe. This eliminates the risk of needlestick injuries and effectively prevents reuse. Furthermore, the elimination of the need for volumetric adjustment of the barrel optimizes injection accuracy.

[0035] Preferably, the bendable flanges are bendable through an angle between 0° and −45° relative to the axial centerline of the syringe. Bending the bendable flanges through this angle allows the extractor element to be disconnected from the plunger in a single fluid transfer motion. Bending the bendable flanges at an angle of, for example, −40° relative to the axial centerline of the syringe securely locks the extractor element inside the hollow plunger, where the restoring tension or compression spring is maintained in a tensioned or compressed state. The extractor element is released from the plunger as soon as the needle holder substantially enters the axial cavity of the plunger, thereby opening the bendable flanges to an angle of, for example, −5° relative to the axial centerline of the syringe. As a result, the restoring tension or compression spring compresses or expands, respectively, pulling or pushing the extractor element coupled to the needle holder inside the hollow plunger, thereby safely locking out the needle inside the syringe.

[0036] More preferably, the plurality of bendable flanges are bendable through an angle between 0° and -40° relative to the axial centerline of the syringe, and even more preferably, are bendable through an angle between 0° and -35°, 5° and -35°, 5° and 30°, or 10° and 30° relative to the axial centerline of the syringe.

[0037] According to further or alternative embodiments, the plurality of bendable flanges comprises at least two bendable flanges. The presence of the two bendable flanges allows the extractor element to be held in place within the hollow plunger. Inserting a needle holder between the bendable flanges uniformly and symmetrically expands the axial bore of the plunger, thereby allowing the extractor element and its associated needle holder to be retracted straight within the syringe. The configuration described herein allows the operator to engage the needle retraction mechanism, with only slight resistance being perceived by the operator. Therefore, operation of the syringe according to the present invention does not feel significantly different to the operation of a conventional syringe. As a result, operation of the syringe according to the present invention is particularly intuitive for medical professionals and other individuals.

[0038] Preferably, the plurality of bendable flanges comprises at least three bendable flanges, more preferably at least four bendable flanges, at least five bendable flanges, or at least six bendable flanges.

[0039] In some embodiments, the hooking means are complementary protrusions extending from both the hollow plunger and the extractor element, which allow the bendable flanges to splay outwardly, thereby smoothly separating the extractor element from the hollow plunger.

[0040] According to a further or alternative embodiment, the internal cavity of the needle holder is defined by a plurality of bendable grips configured to slide over the male protrusions of the extractor element, thereby bending the bendable grips outward, so that the male protrusions of the extractor element are inserted into the internal cavity of the needle holder. The coupling of the extractor element to the needle holder is particularly smooth, so that the operator does not noticeably differ from the operation of a conventional syringe. Meanwhile, the provided bendable grips allow the extractor element to be firmly and irreversibly coupled to the needle holder. This needle retraction mechanism therefore ensures effective retraction of the needle holder, including the needle, within the syringe.

[0041] Preferably, a plurality of bendable grips are configured to slide within the axial bore of the plunger, causing the bendable grips to bend inward, thereby locking the male protrusions of the extractor element within the internal cavity of the needle holder. This bending of the bendable grips toward the interior of the syringe upon engagement of the retraction mechanism further ensures a secure coupling of the extractor element to the needle holder, including the needle. This coupling is particularly effective after retraction has begun, preventing the male protrusions from inadvertently detaching from the internal cavity of the needle holder.

[0042] According to further or alternative embodiments, the bendable grips are bendable through an angle between -20° and 20° relative to the axial centerline of the syringe. Having the bendable grips bendable through an angle of, for example, 15° relative to the axial centerline of the syringe ensures smooth insertion of the male protrusion of the extractor element into the internal cavity of the needle holder. As soon as the needle holder substantially enters the axial cavity of the plunger, thereby opening the bendable flange, the flange bends, for example, through an angle of -15° relative to the axial centerline of the syringe, pushing the bendable grip back. This ensures that the male protrusion is irreversibly coupled, thereby preventing it from inadvertently detaching from the internal cavity of the needle holder.

[0043] Preferably, the plurality of bendable grips are bendable through angles between -15° and 15° relative to the axial centerline of the syringe, more preferably through angles between -10° and 10°, -5° and 10°, or -5° and 5° relative to the axial centerline of the syringe.

[0044] In some embodiments, the plurality of bendable grips comprises at least two bendable grips. The presence of the two bendable grips allows the needle holder's internal cavity to expand evenly and symmetrically, thereby allowing the male protrusion to enter directly into the needle holder's internal cavity. Additionally, upon further retraction, the needle holder's internal cavity narrows evenly and symmetrically around the male protrusion, thereby allowing the extractor element to be securely coupled to the needle holder. The configuration described herein allows the operator to engage the needle retraction mechanism, and the operator perceives only slight resistance. Therefore, operation of the syringe according to the present invention does not feel significantly different to the operator compared to operation of a conventional syringe. As a result, operation of the syringe according to the present invention is particularly intuitive for medical professionals and others.

[0045] Preferably, the plurality of bendable grips comprises at least three bendable grips, more preferably at least four bendable grips, at least five bendable grips, or at least six bendable grips.

[0046] According to some embodiments, the needle holder is configured airtight within the hollow nose end, and the inner wall of the hollow nose end and the outer wall of the needle holder are complementary conical shapes.

[0047] In some embodiments, the syringe of the present invention includes a gasket that fits around the plunger at the end of the needle holder and fits between the outside of the plunger and the inside of the hollow body of the cylindrical barrel, the gasket at least partially overlapping the plurality of bendable flanges.

[0048] In the context of this invention, the term "gasket" relates to a mechanical seal that fills the space between two or more mating surfaces, typically to prevent leakage from or into an assembly under compression. In this example, the gasket is fitted between the outside of the plunger and the inside of the hollow body of the cylindrical barrel.

[0049] While the gasket serves the basic purpose of making the syringe watertight and airtight, the gasket also provides sufficient resistance to act against the expansion of the bendable flange and / or the expansion of the bendable grip, thereby allowing for the appropriate amount of expansion of the bendable flange on the needle holder and / or the appropriate amount of compression of the bendable grip on the male prongs of the extractor element, further improving the single-step coupling of the extractor element to the needle holder and retraction of the two configurations described above within the hollow plunger.

[0050] In some embodiments, the hollow body and hollow nose end of the cylindrical barrel are provided as a single unit. Such embodiments allow the syringe to accommodate only a single type of needle holder and / or a single type of needle. Such syringes include, among others, prefilled syringes and disposable syringes. Such embodiments are particularly advantageous because the needle holder cannot be removed from the syringe at all without actually destroying the syringe.

[0051] In some embodiments, the hollow cylindrical barrel body and hollow nose end are provided as two separate units, with the hollow body extending into a cylindrical or conical fitting having an axial bore adapted to at least partially receive the hollow nose end, and the fitting further comprising a coupling means for connecting the hollow nose end to the hollow cylindrical barrel body. Prior to use of the syringe, such embodiments allow for the selection of a particular needle holder, and in particular a particular needle, to be attached to the hollow nose end of the syringe. By coupling the hollow nose end to the hollow cylindrical barrel body, the needle holder cannot be removed from the syringe once coupled, but the operator is given the opportunity to select a needle prior to injection.

[0052] According to further or alternative embodiments, the extractor element is airtight within the hollow plunger by a sealing ring mounted between the inner wall of the plunger and the outer wall of the extractor element. The sealing ring mounted between the plunger and the extractor element ensures that pressure is not lost as long as the extractor element is coupled to the plunger. When the syringe is completely emptied and the retraction mechanism is engaged, the sealing ring is no longer mounted therebetween, resulting in a loss of pressure.

[0053] In some embodiments, the recovery spring is a tension recovery spring that is disposed within the bore of the rod and coupled to the extractor element. In these embodiments, the tension recovery spring may extend along the length of the rod. Alternatively, in some embodiments, the recovery spring is a compression recovery spring. Such a compression recovery spring may be mounted on the side of the needle holder between the extractor element and the hollow plunger.

[0054] According to some embodiments, the bendable flange has a strength of 600 to 2000 N / mm 2 , more preferably 600 to 2500 N / mm 2The material is constructed from a material having a modulus of elasticity between 0.01 and 0.05. Within this range, the desired amount of bending is achieved and smooth operation of the improved retraction mechanism of the present invention is possible. Here, the term "modulus of elasticity" should be interpreted as a measure of the resistance of an object or substance to being elastically (i.e., semi-permanently) deformed when stress is applied. The modulus of elasticity of an object is defined as the slope of the stress-strain curve in the elastic deformation region.

[0055] The bendable flanges according to some embodiments of the present invention have a resistance of at least 15 N / mm 2 , more preferably at least 20 N / mm 2 The bendable flange is constructed from a material that has an ultimate tensile strength, or tensile strength at break, of 100 psi. This allows the bendable flange to withstand the various stresses imposed on the flange by the retraction mechanism without breaking. The terms "ultimate tensile strength" or "tensile strength at break" are interpreted as the maximum stress that a material can withstand while being stretched or pulled before breaking. Ultimate tensile strength is typically determined by performing a tensile test and recording a stress-strain curve.

[0056] Preferably, the bendable flange has a strength of 600 to 2000 N / mm 2 , more preferably 600 to 2500 N / mm 2 and has an elastic modulus of at least 15 N / mm 2 , more preferably at least 20 N / mm 2 As a result, an optimum balance is found between the amount of bending of the bendable flange and the ultimate tensile strength, thereby achieving smooth release of the extractor element from the hollow plunger.

[0057] According to some embodiments, the bendable grip has a strength of 600 to 2000 N / mm 2 , more preferably 600 to 2500 N / mm 2Within this range, the desired amount of bending of the bendable grip of the needle holder is achieved, allowing for smooth operation of the improved retraction mechanism of the present invention.

[0058] The bendable grip according to some embodiments of the present invention has a resistance of at least 15 N / mm 2 , more preferably at least 20 N / mm 2 The bendable grip is constructed from a material having an ultimate tensile strength or tensile strength at break of 1000 psi or less. This allows the bendable grip to withstand the various stresses imposed on the grip by the retraction mechanism without breaking through.

[0059] Preferably, the bendable grip has a strength of 600 to 2000 N / mm 2 More preferably, between 600 and 2500 N / mm 2 and is made of a material with an elastic modulus of at least 15N / mm 2 , more preferably at least 20 N / mm 2 As a result, an optimum balance is found between the amount of bending of the bendable grip and the ultimate tensile strength, thereby achieving a smooth coupling of the male prong of the extractor element to the needle holder.

[0060] In some embodiments, the extractor element is configured airtight within the hollow plunger, and the inner wall of the hollow plunger and the outer wall of the extractor element are complementary conical shapes.

[0061] In some embodiments of the invention, the syringe is a pre-filled syringe.

[0062] In a further aspect, the present invention relates to a syringe kit, preferably a prefilled syringe kit, said syringe kit comprising a syringe assembly and an injection assembly, said syringe assembly comprising: a. a cylindrical barrel including a hollow body, the hollow body being at least partially filled with an injectable liquid; b. a hollow plunger disposed within the hollow body of the cylindrical barrel; c. a rod connected to or integral with said plunger and extending within said hollow body of said cylindrical barrel, said rod and said plunger each having an axial bore extending therethrough; d. an extractor element disposed inside the axial bore of the plunger and the bore of the rod; e. a restoring tension or compression spring connected to the extractor element; and The injection assembly includes: a. A hollow nose end; and b. a needle holder disposed in the nose end, the needle holder including an internal cavity; Equipped with the syringe assembly and the injection assembly each include a first connecting portion and a second connecting portion, the first connecting portion and the second connecting portion being configured to enable both a coupled kit configuration and an uncoupled kit configuration, the coupled kit configuration hermetically connecting the syringe assembly and the injection assembly, and the internal cavity of the needle holder and the hollow body of the cylindrical barrel being configured to form a continuous channel through which an injection solution can pass, and the uncoupled kit configuration includes a sealing portion that ensures the hermeticity of the syringe assembly without coupling the injection assembly; the extractor element is movable so as to be displaceable between an advanced position surrounded by the plunger, with a portion of the extractor element protruding beyond the distal end of the plunger or protruding from the plunger in the direction of the first connector, and a retracted position fully retracted into the rod and spaced apart from the first connector; the extractor element having a male protrusion extending beyond or from the distal end of the plunger in the advanced position to engage the internal cavity of the needle holder to couple the extractor element to the needle holder, and a catch means defining a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and to maintain the return spring in tension or compression, The syringe kit comprises: The plunger axial bore is defined by a plurality of bendable flanges configured to slide over the needle holder, whereby the bendable flanges bend outward to expand the plunger axial bore, thereby disengaging the extractor element from the plunger and retracting it toward a retracted position.

[0063] In the context of the present invention, the terms "syringe assembly" and "injection assembly" refer to two different parts of the "syringe kit" described herein. Because the kit of the present invention can be in both an assembled and disassembled kit configuration, for convenience, the syringe kit in its assembled configuration and / or in its ready-to-use state will be referred to as the "syringe."

[0064] The syringe kit of the present invention has the advantage that the needle retraction mechanism is significantly improved, is quick to use, safe to use, and intuitive for medical personnel and others to operate. The present invention operates like a normal syringe, with the retraction mechanism automatically engaging as soon as the syringe is emptied.

[0065] In some embodiments, the first and second connectors of each syringe assembly and injection assembly are hermetically coupled to one another. This particular embodiment relates to the configuration of an assembled kit, which can be manufactured and / or supplied as such. In particular, a syringe manufacturer can manufacture the syringe assembly and injection assembly, then fill the hollow body of the barrel with the injection liquid and hermetically couple the syringe assembly to the injection assembly, thereby confining the injection liquid within the coupled syringe kit. The syringe kits described herein are particularly advantageous when a particular injection liquid prefers the use of a particular needle, and the syringe kit is ready to use. In this respect, the kit already includes the appropriate needle, eliminating any doubt from the user about needle selection and how to operate the kit.

[0066] In some embodiments, the first and second connectors of each syringe assembly and injection assembly are disconnected from one another, and the hollow body of the barrel is hermetically sealed by a sealing cap attached to the first connector of the syringe assembly. This particular embodiment relates to a disassembled kit configuration and can be manufactured and / or supplied as such. In particular, a syringe manufacturer can manufacture a syringe assembly and multiple injection assemblies, then fill the hollow body of the barrel with the injection liquid and hermetically seal the hollow body of the barrel with the sealing cap. The syringe kits described herein are particularly advantageous when a specific injection liquid is to be used but the needle selection has not yet been determined. This provides additional freedom of choice for both the manufacturer and the end user, as the needle selection does not have to be immediately determined. In particular, the syringe kit can be provided as a syringe assembly and a single injection assembly, requiring the user to remove the sealing cap and connect both assemblies together before use. This allows the user to postpone needle selection until purchasing the needle kit from the manufacturer. Alternatively, the syringe kit may be provided as a syringe assembly and a number of different injection assemblies, allowing the user to select an injection assembly immediately prior to use, i.e., by connecting the syringe assembly and the selected injection assembly together.

[0067] The advantage of having a syringe kit with separate syringe and injection assemblies is that it provides more packaging options and provides greater user convenience. The syringe kit can be packaged in a single package, or the syringe and injection assemblies can be packaged separately. In this regard, packaging multiple syringe assemblies and / or injection assemblies in a so-called "nested" configuration is considered a safe packaging method.

[0068] In one embodiment, the syringe kit described herein provides a syringe having a needle retraction mechanism as described in one of the above embodiments and considered to be reproduced here in the context of the kit.

[0069] The present invention also relates to the use of a (prefilled) syringe kit for injection of an injection solution in a subject, wherein the syringe assembly and the injection assembly are connected to each other prior to the injection.

[0070] A final aspect of the present invention relates to a method for manufacturing a syringe kit, preferably a prefilled syringe kit, comprising the steps of: Assembling or preparing a syringe assembly, said syringe assembly comprising the following parts: a. A cylindrical barrel including a hollow body; b. a hollow plunger disposed within the hollow body of the cylindrical barrel; c. a rod connected to or integral with the plunger and extending within the hollow body of the cylindrical barrel, the rod and the plunger each having an axial bore extending therethrough; d. an extractor element disposed inside the axial bore of the plunger and the bore of the rod; and e. a restoring tension or compression spring connected to the extractor element; assembling or preparing the syringe assembly, Assembling or preparing a needle assembly, said needle assembly comprising the following parts: a. A hollow nose end; and b. a needle holder disposed in the nose end, the needle holder including an internal cavity; and the syringe assembly and the injection assembly each include a first connector and a second connector, the first connector being sealable to ensure airtightness of the hollow body of the barrel and further capable of being airtightly coupled to the second connector of the injection assembly, and the internal cavity of the needle holder and the hollow body of the cylindrical barrel being configured to form a continuous channel through which an injection solution can pass; the extractor element is movable so as to be displaceable between an advanced position surrounded by the plunger with a portion protruding beyond the distal end of the plunger or protruding from the plunger toward the first connector, and a retracted position fully retracted into the rod and spaced apart from the first connector; the extractor element having a male protrusion extending beyond or from the distal end of the plunger in the advanced position to engage the internal cavity of the needle holder to couple the extractor element to the needle holder, and a catch means defining a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and to maintain the return spring in tension or compression; and assembling or preparing the needle assembly, wherein the plunger axial bore is defined by a plurality of bendable flanges configured to slide over the needle holder, the bendable flanges thereby bending outward to expand the plunger axial bore, thereby disengaging the extractor element from the plunger and retracting it toward a retracted position; filling at least a portion of the hollow body of the cylindrical barrel with an injectable liquid; and hermetically sealing the hollow body of the cylindrical barrel.

[0071] The method preferably produces a syringe kit according to one of the embodiments described above.

[0072] In a preferred embodiment of the present invention, the syringe kit is a prefilled syringe kit.

[0073] In particular, the filling and hermetic sealing steps can be performed by utilizing a specific nested configuration of multiple syringe assemblies and / or injection assemblies. This so-called "nested" configuration is particularly suitable for safely shipping sterile syringe assemblies, for example, from a syringe manufacturing facility to a syringe filling facility. The nested configuration involves placing multiple syringe assemblies on a packaging tray and sealing the tray with a sheet material, such as a Tyvek sheet. The package and its contents may then be sterilized. For filling, the sheet material is removed, and the syringe assemblies are introduced into a filling line. The nested configuration described here can be either an upside-down configuration or a downside-up configuration. In the so-called upside-down configuration, the syringe assembly is filled with the injection liquid through an opening at the top of the barrel. The syringe assembly can then be closed either with a sealing cap or with an injection assembly. In the so-called downside-up configuration, the syringe assembly is filled from the bottom of the barrel and can be closed by inserting a plunger therein.

[0074] [Figure description] The present invention is further explained with the aid of the following figures, which are for the purpose of illustrating the invention and are not intended to, and should not be construed as, limiting the scope of the invention.

[0075] 1A and 1B are general views of a syringe according to an embodiment of the present invention. The syringe depicted therein has an improved needle retraction mechanism and includes a cylindrical barrel 1, the barrel including a hollow body 2 and a hollow nose end 3. The syringe further includes a needle holder 4 disposed in the nose end 3, the needle holder 4 having an internal cavity 5. A hollow plunger 6 is disposed within the hollow body 2 of the cylindrical barrel 1 and connected to a rod 7 that extends within the hollow body 2 of the cylindrical barrel 1, the rod and plunger each having an axial bore extending therethrough. The syringe also includes an extractor element 8 disposed within the axial bore of the plunger 6 and the bore of the rod 7, and a restoring tension spring 9 disposed within the bore of the rod 7 and connected to the extractor element 8. The extractor element 8 can be in an advanced position, partially projecting towards the needle holder 4 and surrounded by the plunger 6, and in a fully retracted position within the rod 7, Hollow nose end 3The extractor element 8 is movable so as to be displaceable between a retracted position, in which the extractor element 8 is spaced from the plunger 6, and a male protrusion 10 that protrudes from the plunger 6 in the advanced position and engages with the internal cavity of the needle holder 5 to join the extractor element 8 to the needle holder 5, and a hooking means 11 that defines the connection between the plunger 6 and the extractor element 8 in the advanced position and maintains the restoring spring 9 in a tensioned state. The axial bore of the plunger 6 is defined by a plurality of bendable flanges 12 configured to slide over the needle holder 5, such that the bendable flanges 12 bend outward and expand the axial bore of the plunger 6, thereby disengaging the extractor element 8 from the plunger 6 and retracting it to the retracted position. Figures 1A and 1B show the syringe in the advanced and retracted positions, respectively. The syringe shown here has the advantage of being intuitively operable for medical personnel and others. The present invention can be operated similarly to a conventional syringe, and the retraction mechanism automatically engages as soon as the syringe is emptied. In particular, the provision of the bendable flange 12 allows the retraction mechanism to be engaged with a single fluid transfer motion, consistent with the operation of a conventional syringe. Furthermore, because volumetric adaptation to the barrel 1 is not required, optimal accuracy of the injection volume is ensured. The bendable flange 12 as depicted here can be bent, in particular, through an angle between 0° and -45° relative to the axial centerline of the syringe. The syringe shown here includes a gasket 14 that surrounds and fits around the plunger 6 at the end of its needle holder 4, and the gasket 14 fits between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, where the gasket 14 at least partially overlaps the bendable flanges 12. In the embodiment shown here, the hollow body 2 of the cylindrical barrel 1 and the hollow nose end 3 are provided as a single unit. The extractor element 8 is configured to be airtight within the hollow plunger 6 by a conical fitting 17 between the inner wall of the plunger 6 and the outer wall of the extractor element 8.

[0076] 2A, 2B, and 2C are detailed views illustrating the movement of a needle retraction mechanism of a syringe according to an embodiment of the present invention upon engagement of the retraction mechanism. In particular, FIGS. 2A-2C show a barrel 1 comprising a hollow body 2, a hollow nose end 3, a needle holder 4, an internal cavity 5 of the needle holder 4, a hollow plunger 6, a rod 7, an extractor element 8, a restoring tension spring 9, a male protrusion 10 of the extractor element 8, a hooking means 11 between the plunger 6 and the extractor element 8, and a bendable flange 12 of the hollow plunger 6. Furthermore, the internal cavity 5 of the needle holder 4 is defined by a plurality of bendable grips 13 configured to slide over the male protrusions 10 of the extractor element 8, thereby bending the bendable grips 13 outward and inserting the male protrusions 10 of the extractor element 8 into the internal cavity 5 of the needle holder 4. The coupling of the extractor element 8 to the needle holder 4 is particularly smooth, so that the operator does not notice any difference when operating the syringe according to the present invention compared to operating a conventional syringe. Meanwhile, the provided bendable grips 13 allow for a robust and irreversible coupling of the extractor element 8 to the needle holder 4. The bendable grips 13 are further configured to slide inside the axial bore of the plunger 6, thereby bending inward and locking the male protrusions 10 of the extractor element 8 into the internal cavity 5 of the needle holder 4. Upon engagement of the retraction mechanism, the bendable grips 13 bend inwardly, as described above, toward the syringe interior, further ensuring a robust coupling of the extractor element 8 to the needle holder 4, including the needle 21. The depicted bendable grips 13 are particularly bendable through angles between -20° and 20° relative to the axial centerline of the syringe. The syringe depicted here further comprises a gasket 14 which is fitted around the plunger 6 at the end of the needle holder 4, the gasket 14 fitting between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, where the gasket 14 at least partially overlaps the plurality of bendable flanges 12.In the embodiment shown here, the hollow body 2 and hollow nose end 3 of the cylindrical barrel 1 are provided as a single unit. The extractor element 8 is configured to seal within the hollow plunger 6 by means of a conical fit 17 between the inner wall of the plunger 6 and the outer wall of the extractor element 8. In particular, FIG. 2A shows the retraction mechanism just prior to engagement, and FIG. 2B shows the male protrusion 10 sliding into the internal cavity 5 of the needle holder 4, thereby coupling the extractor element 8 to the needle holder 4. FIG. 2C shows the retraction mechanism further along, whereby the bendable flange 12 of the hollow plunger 6 expands, thereby releasing the extractor element 8 from the hollow plunger 6 and, in the meantime, tightening the connection between the male protrusion 10 and the needle holder 4 by bending the bending grip 13 inward.

[0077] 3 is a detailed view of the needle retraction mechanism of an empty syringe according to an embodiment of the present invention. This view shows a barrel 1, which comprises a hollow body 2, a hollow nose end 3, a needle holder 4, an internal cavity 5 of the needle holder 4, a hollow plunger 6, a rod 7, an extractor element 8, a restoring tension spring 9, a male protrusion 10 of the extractor element 8, a hooking means 11 between the plunger 6 and the extractor element 8, and a bendable flange 12 of the hollow plunger 6. Furthermore, the internal cavity 5 of the needle holder 4 is defined by a plurality of bendable grips 13, which are configured to slide over the male protrusions 10 of the extractor element 8, thereby bending the bendable grips 13 outward, so that the male protrusions 10 of the extractor element 8 are inserted inside the internal cavity 5 of the needle holder 4. The connection of the extractor element 8 to the needle holder 4 is particularly smooth, so that the operator does not notice any significant difference when operating the (prefilled) syringe kit according to the present invention compared to operating a conventional syringe. Meanwhile, the provided bendable grips 13 allow for a robust and irreversible coupling of the extractor element 8 to the needle holder 4. The plurality of bendable grips 13 are further configured to slide inside the axial bore of the plunger 6, whereby the bendable grips 13 bend inward, thereby locking the male protrusions 10 of the extractor element 8 inside the internal cavity 5 of the needle holder 4. Upon engagement of the retraction mechanism, as described above, the bendable grips 13 bend towards the inside of the syringe, further ensuring a robust coupling of the extractor element 8 to the needle holder 4, including the needle 21. The depicted bendable grips 13 are particularly bendable through an angle between -20° and 20° relative to the axial centerline of the syringe. The (prefilled) syringe kit depicted here further comprises a gasket 14 which is fitted around the plunger 6 at the end of its needle holder 4, the gasket 14 fitting between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, where the gasket 14 at least partially overlaps the plurality of bendable flanges 12.In the embodiment shown here, the hollow body 2 and hollow nose end 3 of the cylindrical barrel 1 are provided as a single unit. The extractor element 8 is arranged in an airtight manner inside the hollow plunger 6 by means of a conical fitting 17 between the inner wall of the plunger 6 and the outer wall of the extractor element 8.

[0078] FIG. 4 is a detailed view of a syringe needle retraction mechanism according to an embodiment of the present invention, comprising a cylindrical or conical fitting 15 for an interchangeable needle holder. The hollow cylindrical barrel body 3 and hollow nose end 2 are provided as two separate units, with the hollow body 2 extending into the fitting 15, which has an axial bore. The axial bore of the fitting 15 is adapted to at least partially receive the hollow nose end 3, which further comprises a first connector 19 for connecting with a complementary second connector 20 integral with the hollow nose end 3, thereby enabling the hollow nose end 3 to be connected to the hollow body 2 of the cylindrical barrel 1. These features allow for the selection of a particular needle holder 4, and in particular a particular needle 21, to be fitted to the hollow nose end 3 of the syringe.

[0079] 5 and 6 are general views of a (prefilled) syringe kit according to an embodiment of the present invention. The syringe kit shown here (as described in the previous figures) has an improved needle retraction mechanism for ease of use and safety during use. The syringe kit comprises a syringe assembly S and an injection assembly I, the latter of which comprises a hollow nose end 3 and a needle holder 4 disposed therein. The needle holder 4 has an internal cavity 5. The syringe assembly S comprises a barrel 1 having a hollow body 2 containing an injection solution L, and a hollow plunger 6 located within the hollow body 2 of the cylindrical barrel 1 and connected to a rod 7 extending within the hollow body 2 of the cylindrical barrel 1, each of which has an axial bore extending therethrough. The syringe assembly S also comprises an extractor element 8 disposed within the axial bore of the plunger 6 and the bore of the rod 7, and a restoring tension spring 9 disposed within the bore of the rod 7 and connected to the extractor element 8. The extractor element 8 is movable between an advanced position, in which it partially projects from the plunger 6 toward the needle holder 4 and is surrounded by the plunger 6, and a retracted position, in which it is completely retracted into the rod 7 and is spaced apart from the needle holder 4. The extractor element 8 also has a male protrusion 10 that projects from the plunger 6 in the advanced position and engages with an internal cavity of the needle holder 5 to connect the extractor element 8 to the needle holder 5, and a hooking means 11 that defines the connection between the plunger 6 and the extractor element 8 in the advanced position and keeps the restoring spring 9 tensioned. The axial bore of the plunger 6 is defined by a plurality of bendable flanges 12 configured to slide over the needle holder 5, such that the bendable flanges 12 bend outward and expand the axial bore of the plunger 6, thereby disengaging the extractor element 8 from the plunger 6 and retracting it to the retracted position. Figures 5 and 6 show the syringe kit in the advanced and retracted positions, respectively. The syringe kits shown herein have the advantage of being intuitive to use for medical personnel and others.The present invention can be operated similarly to a conventional syringe, with the retraction mechanism automatically engaging as soon as the syringe is empty. In particular, the provision of the bendable flange 12 allows the retraction mechanism to be engaged with a single fluid transfer motion, just like a conventional syringe. Furthermore, because volumetric adaptation to the barrel 1 is not required, optimal accuracy of the injection volume is ensured. The bendable flange 12 as depicted here can be bent, in particular, through an angle between 0° and -45° relative to the axial centerline of the syringe. The syringe kit shown here includes a gasket 14 that surrounds and fits around the plunger 6 at the end of the needle holder 4, and the gasket 14 fits between the outside of the plunger 6 and the inside of the hollow body 2 of the cylindrical barrel 1, where the gasket 14 at least partially overlaps the bendable flanges 12. The syringe assembly S and the injection assembly I each include a first connecting portion 19 and a second connecting portion 20 configured to allow for both a coupled and an uncoupled kit configuration, in which the syringe assembly S is airtightly coupled to the injection assembly I, and the internal cavity 5 of the needle holder 4 and the hollow body 2 of the cylindrical barrel 1 are configured to form a continuous channel for the passage of the injection liquid L. Furthermore, the injection assembly I is shown to be comprised of a needle 21 and a needle cap 18.

[0080] A specific embodiment of the present invention is shown in FIG. 7, in which the inner surface of the cylindrical barrel 3 is provided with an annular ring 23 which is adapted to contact and support the outer periphery of the needle holder 4.

[0081] Yet another specific embodiment of the present invention is shown in Figure 8, in which extractor element 8 includes a dead space filler 22 extending from the distal end of extractor element 8. The distal end of said dead space filler 22 provides a base from which the male prongs of extractor element 10 project. The inner surface of hollow plunger 6 is shown in this figure with an annular ring 24 configured to provide a contact surface between extractor element 8 and the inner surface of hollow plunger 6.

[0082] 9 shows a plunger cap 25 and extractor element 8 attached to a recovery tension spring 9. The plunger cap 25 and extractor element 8 further include a plurality of radially extending spring retaining fins 26. In this view, the proximal end of the recovery tension spring 9 is shown with its first two coils surrounding the plunger cap 25, and these two coils are retained by a plurality of spring retaining fins 26. Also in this view, the distal end of the same recovery tension spring 9 is shown with its last two coils surrounding the proximal end of the extractor element 8, and these two coils are also retained by a plurality of spring retaining fins 26.

[0083] 10 shows yet another embodiment in which a substantially cylindrical needle holder 4 is in airtight connection with the hollow nose end of a cylindrical barrel 3. The airtight connection is provided by a gasket 27 provided between the outer periphery of the needle holder 4 and the inner conical surface of the hollow nose end of the cylindrical barrel 3. [Explanation of symbols]

[0084] Numbered parts list S Syringe Assembly I Injection Assembly L Injection 1 cylindrical barrel 2. Hollow body of cylindrical barrel 3. Hollow nose end of cylindrical barrel 4 needle holders 5. Inner cavity of needle holder 6 hollow plungers 7 Rod 8 extractor elements 9 Recovery tension spring 10 Male protrusion of extractor element 11 Hooking means between plunger and extractor element 12. Hollow plunger bendable flange 13 Bendable grip of needle holder 14 Gasket 15 Barrel fitting 16 Seal ring 17 Conical fitting 18 Needle Cap 19 1st connection part 20 2nd connection part 21 needles 22 Dead Space Filler 23 Hollow nose annular ring 24 Plunger annular ring 25 Plunger Cap 26 Spring retaining fin 27 Needle holder gasket

Claims

1. 1. A syringe having an improved needle retraction mechanism, comprising: a. a cylindrical barrel (1) comprising a hollow body (2) and a hollow nose end (3); b. a needle holder (4) disposed at said nose end, said needle holder including an internal cavity (5); c) a hollow plunger (6) disposed within the hollow body of the cylindrical barrel; d. a rod extending within the hollow body of the cylindrical barrel, the rod and the plunger each having an axial bore extending therethrough; e. an extractor element (8) disposed inside the axial bore of the plunger and the bore of the rod; f. A restoring tension or compression spring (9) connected to the extractor element; Equipped with the extractor element is movable so as to be displaceable between an advanced position (A) in which a portion of the extractor element projects towards the needle holder and is surrounded by the plunger, and a retracted position (B) in which the extractor element is fully retracted into the rod and is positioned away from the hollow nose end (3); a male projection (10) projecting in the advanced position to engage an internal cavity of the needle holder to connect the extractor element to the needle holder, and a hooking means (11) defining a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and to maintain the restoring tension or compression spring in tension or compression, The syringe, characterized in that the plunger axial bore is defined by a plurality of bendable flanges (12) configured to slide over the needle holder, the bendable flanges thereby bending outward to expand the plunger axial bore, thereby disengaging the extractor element from the plunger and retracting it toward a retracted position.

2. 2. The syringe of claim 1, wherein the plurality of bendable flanges (12) are bendable through an angle between 0° and −45° relative to an axial centerline of the syringe.

3. 3. A syringe according to claim 1 or 2, characterized in that the plurality of bendable flanges (12) consists of at least two bendable flanges, preferably at least three bendable flanges.

4. A syringe according to any one of claims 1 to 3, characterized in that the hooking means (11) are complementary projections extending from both the hollow plunger (6) and the extractor element (8).

5. 5. The syringe according to claim 1, wherein the internal cavity (5) of the needle holder (4) is defined by a plurality of bendable grips (13) configured to slide over male protrusions (10) of the extractor element (8) such that the bendable grips are bent outward, whereby the male protrusions of the extractor element are inserted into the internal cavity of the needle holder.

6. 6. The syringe according to claim 5, wherein the plurality of bendable grips (13) are configured to slide inside the axial bore of the plunger (6), thereby bending the bendable grips inward, thereby locking the male protrusions (10) of the extractor element inside the internal cavity (5) of the needle holder (4).

7. 7. The syringe according to claim 5 or 6, wherein the plurality of bendable grips (13) are bendable through an angle between -20° and 20° relative to the axial centerline of the syringe.

8. A syringe according to any one of claims 5 to 7, characterized in that the plurality of bendable grips (13) consists of at least two bendable grips, preferably at least three bendable grips.

9. 8. The syringe according to claim 1, wherein the needle holder (4) is arranged airtight inside the hollow nose end (3), and the inner wall of the hollow nose end and the outer wall of the needle holder are of complementary conical shape.

10. 10. The syringe according to any one of claims 1 to 9, further comprising a gasket (14) that fits around the plunger (6) at the end of the needle holder and fits between the outside of the plunger and the inside of the hollow body (2) of the cylindrical barrel (1), the gasket at least partially overlapping the plurality of bendable flanges (12).

11. A syringe according to any one of claims 1 to 10, characterized in that the hollow body (2) and hollow nose end (3) of the cylindrical barrel (1) are provided as a single unit.

12. 12. The syringe according to any one of claims 1 to 11, wherein the hollow body (2) and hollow nose end (3) of the cylindrical barrel (1) are provided as two independent units, the hollow body extending in a fitting (15) having an axial bore adapted to at least partially receive the hollow nose end, and the fitting is further configured to comprise connecting means (19, 20) for connecting the hollow nose end to the hollow body of the cylindrical barrel.

13. 13. A syringe according to any one of claims 1 to 12, characterized in that the extractor element (8) is configured in an airtight manner inside the hollow plunger (6) by means of a sealing ring (16) fitted between the inner wall of the plunger and the outer wall of the extractor element.

14. 14. A syringe according to any one of claims 1 to 13, characterized in that the extractor element (8) is arranged in an airtight manner inside the hollow plunger (6), the inner wall of the hollow plunger and the outer wall of the extractor element being of complementary conical shape.

15. A syringe kit, preferably a prefilled syringe kit, said syringe kit comprising a syringe assembly (S) and an injection assembly (I), The syringe assembly includes: a. a cylindrical barrel (1) including a hollow body (2), the hollow body being at least partially filled with an injectable liquid (L); b. A hollow plunger (6) disposed within the hollow body of the cylindrical barrel; c. a rod, at least a portion of which extends within the hollow body of the cylindrical barrel, the rod and the plunger each having an axial bore extending therethrough; d. an extractor element (8) disposed inside the axial bore of the plunger and the bore of the rod; e. A restoring tension or compression spring (9) connected to the extractor element; and The injection assembly includes: a. A hollow nose end (3), and b. a needle holder (4) disposed in said nose end, said needle holder including an internal cavity (5); Equipped with the syringe assembly and the injection assembly each comprise a first connecting part (19) and a second connecting part (20), the first connecting part and the second connecting part being configured to allow both a coupled kit configuration and an uncoupled kit configuration, the coupled kit configuration being configured to hermetically couple the syringe assembly and the injection assembly, the internal cavity of the needle holder and the hollow body of the cylindrical barrel being configured to form a continuous channel allowing the passage of an injection liquid, and the uncoupled kit configuration including a sealing part that ensures the hermeticity of the syringe assembly without coupling the injection assembly; the extractor element is movable so as to be displaceable between an advanced position (A) in which a portion of the extractor element projects towards the first connector and is surrounded by the plunger, and a retracted position (B) in which the extractor element is fully retracted into the rod and is located away from the first connector; the extractor element has a male projection (10) that projects in the advanced position and engages with the internal cavity of the needle holder to connect the extractor element to the needle holder, and a catch means (11) that defines a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and to maintain the restoring tension or compression spring in tension or compression, The syringe kit comprises:

1. A syringe kit, comprising: a syringe body having a plunger axial bore defined by a plurality of bendable flanges (12) configured to slide over the needle holder, the bendable flanges thereby bending outward to expand the plunger axial bore, thereby disengaging the extractor element from the plunger and retracting it toward a retracted position.

16. 16. A syringe kit according to claim 15, wherein the first and second connections (19, 20) of the syringe assembly (S) and the injection assembly (I), respectively, are airtightly connected to each other.

17. 16. A syringe kit according to claim 15, wherein the first connecting portion (19) and the second connecting portion (20) of the syringe assembly (S) and the injection assembly (I), respectively, are disconnected from each other, and the hollow body (2) of the cylindrical barrel (1) is hermetically sealed by a sealing cap fitted to the first connecting portion of the syringe assembly.

18. 18. A syringe kit according to any one of claims 15 to 17, characterized in that the plurality of bendable flanges (12) are bendable through an angle between 0° and -45° relative to an axial centerline of the syringe assembly.

19. A syringe kit according to any one of claims 15 to 18, characterized in that the hooking means (11) are complementary protrusions extending from both the hollow plunger (6) and the extractor element (8).

20. 20. A syringe kit according to any one of claims 15 to 19, characterized in that the internal cavity (5) of the needle holder (4) is defined by a plurality of bendable grips (13) configured to slide over male protrusions (10) of the extractor element (8) so that the bendable grips are bent outward, whereby the male protrusions of the extractor element are inserted into the internal cavity of the needle holder.

21. 21. A syringe kit according to claim 20, wherein the plurality of bendable grips (13) are configured to slide inside the axial bore of the plunger (6), thereby bending the bendable grips inward, thereby locking the male protrusions (10) of the extractor element (8) inside the internal cavity (5) of the needle holder (4).

22. 22. The syringe kit according to claim 20 or 21, wherein the plurality of bendable grips (13) are bendable through an angle between -20° and 20° relative to the axial centerline of the syringe assembly.

23. 23. A syringe kit according to any one of claims 15 to 22, characterized in that the needle holder (4) is arranged airtight inside the hollow nose end (3), and the inner wall of the hollow nose end and the outer wall of the needle holder are of complementary conical shape.

24. The syringe kit according to any one of claims 15 to 23, further comprising a gasket (14) that fits around the plunger (6) at the end of the needle holder and fits between the outside of the plunger and the inside of the hollow body (2) of the cylindrical barrel (1), the gasket at least partially overlapping the plurality of bendable flanges (12).

25. A syringe kit according to any one of claims 15 to 24, characterized in that the extractor element (8) is configured in an airtight manner inside the hollow plunger (6) by means of a sealing ring (16) fitted between the inner wall of the plunger and the outer wall of the extractor element.

26. A syringe kit according to any one of claims 15 to 25, characterized in that the extractor element (8) is arranged in an airtight manner inside the hollow plunger (6), the inner wall of the hollow plunger and the outer wall of the extractor element being of complementary conical shape.

27. Use of a syringe kit for injection of an injection solution in a subject according to any one of claims 15 to 26, wherein the syringe assembly (S) and the injection assembly (I) are connected to each other prior to injection.

28. 1. A method for producing a syringe kit, preferably a prefilled kit, comprising: Assembling or preparing a syringe assembly, said syringe assembly comprising the following parts: a. a cylindrical barrel (1) comprising a hollow body (2); b. A hollow plunger (6) disposed within the hollow body of the cylindrical barrel; c. a rod (7), at least a portion of which extends within the hollow body of the cylindrical barrel, the rod and the plunger each having an axial bore extending therethrough; d. an extractor element (8) disposed inside the axial bore of the plunger and the bore of the rod; e. A restoring tension or compression spring (9) connected to the extractor element; assembling or preparing the syringe assembly, Assembling or preparing an injection assembly, said injection assembly comprising the following parts: a. A hollow nose end (3), and b. a needle holder (4) disposed in said nose end, said needle holder including an internal cavity (5); and The syringe assembly and the injection assembly each comprise a first connecting part (19) and a second connecting part (20), the first connecting part being sealable to ensure airtightness of the hollow body of the cylindrical barrel and further airtightly connectable with the second connecting part of the injection assembly, and the internal cavity of the needle holder and the hollow body of the cylindrical barrel being configured to form a continuous channel through which an injection liquid can pass; the extractor element is movable so as to be displaceable between an advanced position (A) in which a portion thereof projects toward the first connector and is surrounded by the plunger, and a retracted position (B) in which the extractor element is fully retracted into the rod and is positioned away from the first connector; the extractor element having a male projection (10) that projects in the advanced position and engages with the internal cavity of the needle holder to couple the extractor element to the needle holder, and a catch means (11) that defines a connection between the plunger and the extractor element to maintain the extractor element in the advanced position and to maintain the restoring tension or compression spring in tension or compression; and assembling or preparing the injection assembly, wherein the plunger axial bore is defined by a plurality of bendable flanges (12) configured to slide over the needle holder, the bendable flanges thereby bending outward to expand the plunger axial bore, thereby disengaging the extractor element from the plunger and retracting it towards a retracted position; - filling at least a portion of the hollow body of the cylindrical barrel with an injectable liquid; - hermetically sealing the hollow body of the cylindrical barrel; A method comprising:

29. The method according to claim 28, wherein the syringe kit is a kit according to any one of claims 15 to 26.

Images